Machine provided with an automatic firearm



M. BIRKIGT March 30, 1937.

MACHINE PROVIDED WITH AN AUTOMATIC FIREARM Filed Dec. 26, 1934 INVENTOR Marc Birkigt BY ATTORNEYS Patented Mar. 30, 19 37 monmn rnovrnnn WITH AN AUTOMATIQ Marc Birkigt, Bois-Colombes, France Application December 26, 1934, Serial No. 759,279

In Belgium November 20, 1934 izclai s. (01. 89-375) The present invention relates to machines, and

more especially aircrafts, such as airplanes, provided with an automatic firearm. The invention is more-especially, although not exclusively, concerned with machines of this kind in which the firearm-is ofthe open breech'type, that is :0 32y the breech is open when the arm is ready The object of the present invention is to provide a machine of the type above referred to which is better adapted to meet the requirements of practice.

Machines of this kind are provided with means for fixing thereto one of the parts of the firearm, l5 and means cooperating with another part of the firearm for maintaining the axis thereof in a' substantially stationary position with respect to the machine. The essential feature of the present invention consists in fixing the first mentioned part of the firearm to the machine through means permitting certain elastic displacements, at least in one direction, of the firearm with respect to the machine.

Other characteristic features of thepresent invention will result from the following detailed description of a specific embodiment thereof.

. A preferred embodiment of the present invention will be hereinafter described, with reference to the accompanying drawing, given merely by way of example, and in which:

.Fig. 1 is a dlagrammatlcal view of the front part of the fuselage ofv an airplane provided with a gun-engine unit and made according to the present invention;

tion, through the axis of the propeller shaft, of the device for fixing the gun to the engine, according to the present invention;

Fig. 3 shows, also on a larger scale, a vertical,

40 section on the line 111-111 of Fig. Lof the means for connecting the rear partof the gun to the i engine.

In the embodiment, shown by the drawing,

which specifically relates to the constructionof. 55 a gun-engine unit lorau airplane, the airplane,

of the propeller, said shaft 4 being made tubular for this purpose. At the rear part of the gun there is provided a device 5 adapted to maintain the axis of said gun in a substantially fixed position with respect to the engine 3. Advantageously, this device is made, in the known manner, as shown by Fig. 3,

so as to be able to permit a sliding displacement of the rear part of the gun with respect to the engine, said sliding displacement being intended, in prior systems, to permit dilatation of the gun tube under the effect of the heating thereof.

But, up to the present time, the barrel l of the gunwas rigidly fixed to the engine. Now, according to the present invention, the fixation of the gun to the engine is, on the contrary, so devised as to permit axial elastic displacements of the barrel of the gun with respect to the engine, at least in one direction.

For this purpose I provide in the casing 2 of the speed reducing gear, guiding means adapted to permit the gun barrel to slide with respect to said casing.

Furthermore, I provide, on atleast one side of said guiding means, and preferably on both sides thereof, elastic stopping means, having preferably a certain compression in the state of rest, adapted to maintain elastically the gun barrel in a given position by applying against a stationary stop a projection carried by said gun barrel. v

This arrangement may be made, for instance,

as specifically shown by the drawing -above re- "ferred to. Fig. 2 shows, on a larger scale, a vertical sec- As shown in Fig. 2, the rear wall ofcasing 2 is provided with a guiding member 6, coaxial with the propeller. be for instance mounted by having ittightly held 5 between the two halves of the casing and it may consist of a ring provided with flanges l and 8 disposed on either side thereof respectively, so that, after assembly ofthe various elements, flanges 1 and 8 are disposed on the outside and the inside of casing 2 respectively.

In this guiding member 6 there is mounted, with a Working fit; a sleeve 9 provided,' on the inside of the casing, with a fiangelll adapted to bear against flange 8. Said sleeve 9 extends;

for instance a little beyond guiding member 6,

This guiding member may at its rear end, with a flange l3 adapted to be applied against stop ll. Between said flange l3 and flange 7 of guiding member 6, I insert a spring it, or preferably a. plurality of springs 5 each mounted'in a housing provided in the front face of flange i3.

In order to give a suitable initial tension to said springs i i, I-provide on guiding member 6 a stop capable of coacting with the rear face of flange I3 so as to limit the position of said flange toward the rear. For instance, as shown in the drawing, this stop consists of a kind of cap Hi the end of which is provided with a'hole for the gun barrel and which screws on a tubular extension of flange I whereby springs l6 and flange 83 are enclosed in a kind-of casing constituted by tubular part i5 and cap IS.

The various elements of the device are so di-,- mensioned that the elasticity of the elastic system corresponds to the working that will be hereinafter described. Preferably, in the state of rest, therrear end of sleeve 9 is in contact with the front end of. sleeve l2.

A strong spring I! is inserted between flange 2 l0 and a stop l8 carried by the barrel l of the gun. For instance, as shownby the drawing,

this stop consists of the rear edge of a tube surrounding the gun barrel and fixed in position by a nut l9, which maybe rigid with flre protecof this force, the device above described will work in the following manner:

Under the efiect of the recoil caused by the flring of a shot, spring I! is only very little compressed if the working is normal, on the contrary, in the case of an exaggerated recoil movement, this spring is more compressed'and absorbs the shock transmitted to the airplane.

As for springs l4 they serve to absorb the shocks that are produced when the organs of the gun come back to the flring position.

In the case of guns of the open breech type, this return movement of the parts of the gun produces important shocks. However, in this case, springs It shall advantageously be given an initial compression such that they have practically no action during normal firing, but are compressed only when the last cartridge is flred.

This is because the shock produced by the return of the movable parts of the gun into position is much more violent after the last shot has been flred since, in this case, the return movement is no longer braked by the insertion of a new 0 cartridge into the gun.

It should benoted that the two systems of springs do not compensate each other but always act separately.

Of course, while it has been supposed that the front part of the gun is fixed to the casing of the speed reducing gear of an airplane engine, this is not a. necessary ,feature of the invention.

In a. general manner, while I have, in the above description, disclosed what I deem to be a practical and eflicient embodiment of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within claims.

What I claim is: 4

1. In combination, an aircraft engine, a ho]- low propeller shaft, a speed reducing gear for connecting saidengine with said propeller shaft, a casing for said speed reducing gear, a gun the barrel of which extends through said propeller shaft in coaxial relation therewith, a guiding annular member carriedby said casing, a sleeve mounted in said guiding member with a working flt and surrounding the gun barrel, which is mounted therein with a working flt, a flange on said sleeve at the front end thereof, a projection on said gun'barrel, a spring interposed between said projection and said flange, so as to oppose the recoil movement of the gun with respect to said casing, and'means'carried by the engine for slidably guiding the rear part of the gun. so as to keep the axis thereof parallel to the direction in which the barrel of the gun is allowed to slide in said sleeve.

2. In combination, an aircraft engine, a hollow propeller shaft, a. speed reducing gear for connecting said engine with said propeller shaft, a casing for said speed reducing gear, a gun the barrel of which extends through said hollow propeller shaft in coaxial relation therewith, a guiding annular member carried'by said casing, a sleeve mounted in said guiding member with a working fit and surrounding the gun barrel, which is mounted therein with a working'flt, a flange on said sleeve at the front end thereof, a projection on said gun barrel, a spring interposed between said projection and said flange, so as to oppose the recoil movement of'the gun with respect to said casing, another sleeve mounted on the gun barrel behind the first mentioned sleeve, a flange at the rear end of the second mentioned sleeve, a projection on the gun barrel adapted to cooperate with the rear face of said second mentioned sleeve, a spring interposed between said last mentioned flange and the rear face of said guiding member, and means carried by the engine for slidably guiding the rear part of the gun so as to keep the axis thereof parallel to the direction in which the barrel of the gun is allowed to slide in said sleeve.

3. A combination according to claim 2 further including means carried by said guiding member for adjusting'the initial compression of the secondmentioned spring.

'4. In an aircraft, an automatic gun carried by said aircraft, at least one preliminarily stressed spring for elastically connecting a part of said gun to said aircraft adapted to oppose recoil movement, the preliminary stressing of said spring being greater than the force of normal recoil, and means for-guiding another part of the gun with respect to said aircraft so as to the scope of the appended keep the axis of said gun in substantially flxed relation with respect to said aircraft.

5. In an aircraft, an automatic-gun with a barrel carriedby said aircraft, at least one preliminarily stressed spring for connecting a part of said barrel to said aircraft adapted to oppose recoil movement, the preliminary stressing of said spring being greater than the force of normal recoil, and means for guiding another part of the gun with respect to said aircraft soas to keep the axis of said gun in substantially fixed relation with respect to said aircraft.

6. In an aircraft, an automatic gun with a barrel, means carried by said aircraft for slidably supporting the barrel of said gun, at least one preliminarily stressed spring for yieldingly opposing recoil movements of said barrel with respect to the aircraft, the preliminary stressing of said spring being greater than the force of normal recoil, and means for guiding another part of the gun with respect to said aircraft, so as to keep the axis of said gun in substantially fixed relation with respect to said aircraft.

'7. In combination, an automatic gun, a support for said automatic gun, at least one preliminarily stressed spring for elastically connecting a part of said gun to said support adapted to oppose recoil movements, the preliminary stressing of said spring being greater than the force of normal recoil, and means for guiding another part of the gun with respect to said support so as to keep the axis of said gun in substantially fixed relation with respect to said support.

8. In combination, an automatic gun with a barrel, a support for said gun, at least one preliminarily stressed spring for connecting a part of said barrel to said support adapted to oppose recoil movements, the preliminary stressing of said spring being greater than the force of normal recoil, and means for guiding another part of the gun with respect to said support, so as to keep the axis of said gun in substantially fixed relation with respect to said support.

9. In combination, an automatic gun with a barrel, a support for said gun comprising a guiding annular member carried by said support, a sleeve mounted in said guiding member with a working fit surrounding the gun barrel which is mounted therein with a working fit, a flange on said sleeve at the front end thereof, a projection on said gun barrel, a preliminarily stressed spring interposed between said projection and said flange, the preliminary stressing of said spring being greater than the force of normal recoil so as to oppose the recoil movement of the gun with respect to said support, a second projection on said gun barrel behind said sleeve, said second projection being held against the rear end of said sleeve by said spring, and means carried 5 by the support for slidably guiding the rear part of the gun so as to keep the axis thereof parallel to the direction 'in which the barrel of the gun is allowed to slide in said sleeve.

10. In combination, an automatic gun with a barrel, a support for said gun comprising a guiding annular member carried by said support, a sleeve mounted in said guiding member with the working fit and surrounding the gun barrel which is mounted therein with a working fit, a

flange on said sleeve at the front end thereof, a projection on said gun barrel, a preliminarily stressed spring interposed between said projection and said flange, the preliminary stressing of said spring being greater than the force of normal recoil, so as to oppose the recoil movement of the gun with respect to said support, a second projection on said gun barrel behind said sleeve, said second projection being held against the rear end of said sleeve by said spring, means for holding the flange of said sleeve against the front side of said guiding annular member, and means carried by the support for slidably guiding the rear part of the gun so as to keep the axis thereof parallel to the direction in which the barrel of the gun is allowed to slide in said sleeve.

11. A mounting arrangement for aircraft guns comprising, an aircraft engine, a hollow propeller shaft, a speed reducing gear for connecting said engine with said propeller shaft, a casing for said speed reducing gear, a gunthe barrel of which extends through said propeller shaft in coaxial relation therewith, a guiding annular member carried by said casing, a sleeve mounted in said guiding member with a working fit and surrounding the gun barrel which ismounted therein with aworking fit, a flange on said sleeve at the front end thereof, a projection on said gun barrel, a preliminarily stressed spring interposed between said projectionand said flange, the

preliminary stressing of said spring being greater than the force of normal recoil so as to oppose the recoil movement of the gun with respect to said casing, a second projection on said gun barrel behind said sleeve, said second projection being held against the rear end of said sleeve by said spring, and means carried by the aircraft engine for slidably guiding the rear part of the gun so as to keep the axis thereof parallel to the direction in which the barrel of the gun is al- I lowed to slide in said sleeve.

12. -In an aircraft, an aircraft engine, an automatic gun carried by said aircraft engine, at least one preliminarily stressed spring for elastically connecting a part of said gun to said aircraft engine to oppose recoil movement, the preliminary stressing of said spring being greater than the force of normal recoil, and means attached to said aircraft engine for guiding another part of the gun with respect to said aircraft so as to keep the axis of said gun in substantially fixed MARC BIRKIGT. 

